The Significance of the Control: Critiquing Scientific Research Methods

History has shown us that the inclusion of a control group is vital to our understanding of research results. For example, in 1700 and 1800s, many highly respected physicians, including Benjamin Rush, treated most medical conditions with bloodletting - the process of cutting open the skin and severing blood vessels. Bloodletting was assumed to be beneficial. Also during that time, a significant number of sailors died during extended sea voyages. Those skeptical of blood letters’ claims, including, Alexander Hamilton, and those wanting to find a cure for sailors, including James Lind, Gilbert Blane conducted the first clinical trials of bloodletting and treatments for scurvy which included treatment and control groups. Those examining bloodletting clearly indicated that not only was it ineffective, but it was actually more detrimental to mortality rates than doing nothing. Clinical trials with a control group also clearly indicated that citrus was the key to reducing death rates in sailors due to scurvy to nearly zero. In the present investigation, the authors analyzed Emily Metz’s Masters Thesis, in which data suggested all three different training methods to teach students to free-pour a standard serving of alcohol were effective. However, the original study failed to include a control group, so it was impossible to determine if students improved due to the training methods or to some other factor (e.g., practice effects). Metz later added a control group. The data including the control group clearly show the free-pour methods were effective in teaching students to accurately free pour standard servings of alcohol. Without the control group, it would be impossible to know if the manipulation caused improvement in students’ free-pours